From 458120dd40db6b4df55a4e96b650e16798ef06a0 Mon Sep 17 00:00:00 2001 From: cinap_lenrek Date: Tue, 3 May 2011 11:25:13 +0000 Subject: add hg and python --- sys/src/cmd/python/Objects/stringlib/fastsearch.h | 104 ++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 sys/src/cmd/python/Objects/stringlib/fastsearch.h (limited to 'sys/src/cmd/python/Objects/stringlib/fastsearch.h') diff --git a/sys/src/cmd/python/Objects/stringlib/fastsearch.h b/sys/src/cmd/python/Objects/stringlib/fastsearch.h new file mode 100644 index 000000000..8f79c360d --- /dev/null +++ b/sys/src/cmd/python/Objects/stringlib/fastsearch.h @@ -0,0 +1,104 @@ +/* stringlib: fastsearch implementation */ + +#ifndef STRINGLIB_FASTSEARCH_H +#define STRINGLIB_FASTSEARCH_H + +/* fast search/count implementation, based on a mix between boyer- + moore and horspool, with a few more bells and whistles on the top. + for some more background, see: http://effbot.org/stringlib */ + +/* note: fastsearch may access s[n], which isn't a problem when using + Python's ordinary string types, but may cause problems if you're + using this code in other contexts. also, the count mode returns -1 + if there cannot possible be a match in the target string, and 0 if + it has actually checked for matches, but didn't find any. callers + beware! */ + +#define FAST_COUNT 0 +#define FAST_SEARCH 1 + +Py_LOCAL_INLINE(Py_ssize_t) +fastsearch(const STRINGLIB_CHAR* s, Py_ssize_t n, + const STRINGLIB_CHAR* p, Py_ssize_t m, + int mode) +{ + long mask; + Py_ssize_t skip, count = 0; + Py_ssize_t i, j, mlast, w; + + w = n - m; + + if (w < 0) + return -1; + + /* look for special cases */ + if (m <= 1) { + if (m <= 0) + return -1; + /* use special case for 1-character strings */ + if (mode == FAST_COUNT) { + for (i = 0; i < n; i++) + if (s[i] == p[0]) + count++; + return count; + } else { + for (i = 0; i < n; i++) + if (s[i] == p[0]) + return i; + } + return -1; + } + + mlast = m - 1; + + /* create compressed boyer-moore delta 1 table */ + skip = mlast - 1; + /* process pattern[:-1] */ + for (mask = i = 0; i < mlast; i++) { + mask |= (1 << (p[i] & 0x1F)); + if (p[i] == p[mlast]) + skip = mlast - i - 1; + } + /* process pattern[-1] outside the loop */ + mask |= (1 << (p[mlast] & 0x1F)); + + for (i = 0; i <= w; i++) { + /* note: using mlast in the skip path slows things down on x86 */ + if (s[i+m-1] == p[m-1]) { + /* candidate match */ + for (j = 0; j < mlast; j++) + if (s[i+j] != p[j]) + break; + if (j == mlast) { + /* got a match! */ + if (mode != FAST_COUNT) + return i; + count++; + i = i + mlast; + continue; + } + /* miss: check if next character is part of pattern */ + if (!(mask & (1 << (s[i+m] & 0x1F)))) + i = i + m; + else + i = i + skip; + } else { + /* skip: check if next character is part of pattern */ + if (!(mask & (1 << (s[i+m] & 0x1F)))) + i = i + m; + } + } + + if (mode != FAST_COUNT) + return -1; + return count; +} + +#endif + +/* +Local variables: +c-basic-offset: 4 +indent-tabs-mode: nil +End: +*/ -- cgit v1.2.3